/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    AbstractFileSaver.java
 *    Copyright (C) 2004-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.core.converters;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.util.Enumeration;
import java.util.Vector;

import weka.core.Environment;
import weka.core.EnvironmentHandler;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.Utils;

/**
 * Abstract class for Savers that save to a file
 * 
 * Valid options are:
 * 
 * -i input arff file <br>
 * The input filw in arff format.
 * <p>
 * 
 * -o the output file <br>
 * The output file. The prefix of the output file is sufficient. If no output
 * file is given, Saver tries to use standard out.
 * <p>
 * 
 * 
 * @author Richard Kirkby (rkirkby@cs.waikato.ac.nz)
 * @author Stefan Mutter (mutter@cs.waikato.ac.nz)
 * @version $Revision$
 */
public abstract class AbstractFileSaver extends AbstractSaver implements OptionHandler, FileSourcedConverter, EnvironmentHandler {

    /** ID to avoid warning */
    private static final long serialVersionUID = 2399441762235754491L;

    /** The destination file. */
    private File m_outputFile;

    /** The writer. */
    private transient BufferedWriter m_writer;

    /** The file extension of the destination file. */
    private String FILE_EXTENSION;

    /** the extension for compressed files */
    private final String FILE_EXTENSION_COMPRESSED = ".gz";

    /** The prefix for the filename (chosen in the GUI). */
    private String m_prefix;

    /** The directory of the file (chosen in the GUI). */
    private String m_dir;

    /**
     * Counter. In incremental mode after reading 100 instances they will be written
     * to a file.
     */
    protected int m_incrementalCounter;

    /** use relative file paths */
    protected boolean m_useRelativePath = false;

    /** Environment variables */
    protected transient Environment m_env;

    /**
     * resets the options
     * 
     */
    @Override
    public void resetOptions() {

        super.resetOptions();
        m_outputFile = null;
        m_writer = null;
        m_prefix = "";
        m_dir = "";
        m_incrementalCounter = 0;
    }

    /**
     * Gets the writer
     * 
     * @return the BufferedWriter
     */
    public BufferedWriter getWriter() {

        return m_writer;
    }

    /** Sets the writer to null. */
    public void resetWriter() {

        m_writer = null;
    }

    /**
     * Gets ihe file extension.
     * 
     * @return the file extension as a string.
     */
    @Override
    public String getFileExtension() {

        return FILE_EXTENSION;
    }

    /**
     * Gets all the file extensions used for this type of file
     * 
     * @return the file extensions
     */
    @Override
    public String[] getFileExtensions() {
        return new String[] { getFileExtension() };
    }

    /**
     * Sets ihe file extension.
     * 
     * @param ext the file extension as a string startin with '.'.
     */
    protected void setFileExtension(String ext) {

        FILE_EXTENSION = ext;
    }

    /**
     * Gets the destination file.
     * 
     * @return the destination file.
     */
    @Override
    public File retrieveFile() {

        return m_outputFile;
    }

    /**
     * Sets the destination file.
     * 
     * @param outputFile the destination file.
     * @throws IOException throws an IOException if file cannot be set
     */
    @Override
    public void setFile(File outputFile) throws IOException {

        m_outputFile = outputFile;
        setDestination(outputFile);

    }

    /**
     * Sets the file name prefix
     * 
     * @param prefix the file name prefix
     */
    @Override
    public void setFilePrefix(String prefix) {

        m_prefix = prefix;
    }

    /**
     * Gets the file name prefix
     * 
     * @return the prefix of the filename
     */
    @Override
    public String filePrefix() {

        return m_prefix;
    }

    /**
     * Sets the directory where the instances should be stored
     * 
     * @param dir a string containing the directory path and name
     */
    @Override
    public void setDir(String dir) {

        m_dir = dir;
    }

    /**
     * Gets the directory
     * 
     * @return a string with the file name
     */
    @Override
    public String retrieveDir() {

        return m_dir;
    }

    /**
     * Set the environment variables to use.
     * 
     * @param env the environment variables to use
     */
    @Override
    public void setEnvironment(Environment env) {
        m_env = env;
        if (m_outputFile != null) {
            try {
                // try and resolve any new environment variables
                setFile(m_outputFile);
            } catch (IOException ex) {
                // we won't complain about it here...
            }
        }
    }

    /**
     * Returns an enumeration describing the available options.
     * 
     * @return an enumeration of all the available options.
     */
    @Override
    public Enumeration<Option> listOptions() {

        Vector<Option> newVector = Option.listOptionsForClassHierarchy(this.getClass(), AbstractFileSaver.class);
        // Vector<Option> newVector = new Vector<Option>();

        newVector.addElement(new Option("\tThe input file", "i", 1, "-i <the input file>"));

        newVector.addElement(new Option("\tThe output file", "o", 1, "-o <the output file>"));

        return newVector.elements();
    }

    /**
     * Parses a given list of options. Valid option is:
     * <p>
     * 
     * -i input arff file <br>
     * The input filw in arff format.
     * <p>
     * 
     * -o the output file <br>
     * The output file. The prefix of the output file is sufficient. If no output
     * file is given, Saver tries to use standard out.
     * <p>
     * 
     * 
     * @param options the list of options as an array of strings
     * @exception Exception if an option is not supported
     */
    @Override
    public void setOptions(String[] options) throws Exception {

        Option.setOptionsForHierarchy(options, this, AbstractFileSaver.class);
        String outputString = Utils.getOption('o', options);
        String inputString = Utils.getOption('i', options);

        ArffLoader loader = new ArffLoader();

        resetOptions();

        if (inputString.length() != 0) {
            try {
                File input = new File(inputString);
                loader.setFile(input);
                setInstances(loader.getDataSet());
            } catch (Exception ex) {
                ex.printStackTrace();
                throw new IOException("No data set loaded. Data set has to be in ARFF format.");
            }
        }
        if (outputString.length() != 0) {
            boolean validExt = false;
            for (String ext : getFileExtensions()) {
                if (outputString.endsWith(ext)) {
                    validExt = true;
                    break;
                }
            }
            // add appropriate file extension
            if (!validExt) {
                if (outputString.lastIndexOf('.') != -1) {
                    outputString = (outputString.substring(0, outputString.lastIndexOf('.'))) + FILE_EXTENSION;
                } else {
                    outputString = outputString + FILE_EXTENSION;
                }
            }
            try {
                File output = new File(outputString);
                setFile(output);
            } catch (Exception ex) {
                throw new IOException("Cannot create output file (Reason: " + ex.toString() + "). Standard out is used.");
            }
        }
    }

    /**
     * Gets the current settings of the Saver object.
     * 
     * @return an array of strings suitable for passing to setOptions
     */
    @Override
    public String[] getOptions() {
        Vector<String> result;

        result = new Vector<String>();
        for (String s : Option.getOptionsForHierarchy(this, AbstractFileSaver.class)) {
            result.add(s);
        }

        if (m_outputFile != null) {
            result.add("-o");
            result.add("" + m_outputFile);
        }

        if (getInstances() != null) {
            result.add("-i");
            result.add("" + getInstances().relationName());
        }

        return result.toArray(new String[result.size()]);
    }

    /** Cancels the incremental saving process. */
    @Override
    public void cancel() {

        if (getWriteMode() == CANCEL) {
            if (m_outputFile != null && m_outputFile.exists()) {
                if (m_outputFile.delete()) {
                    System.out.println("File deleted.");
                }
            }
            resetOptions();
        }
    }

    /**
     * Sets the destination file (and directories if necessary).
     * 
     * @param file the File
     * @exception IOException always
     */
    @Override
    public void setDestination(File file) throws IOException {

        boolean success = false;
        String tempOut = file.getPath();
        try {
            if (m_env == null) {
                m_env = Environment.getSystemWide();
            }
            tempOut = m_env.substitute(tempOut);
        } catch (Exception ex) {
            // don't complain about it here...
            // throw new IOException("[AbstractFileSaver]: " + ex.getMessage());
        }
        file = new File(tempOut);
        String out = file.getAbsolutePath();
        if (m_outputFile != null) {
            try {
                if (file.exists()) {
                    if (!file.delete()) {
                        throw new IOException("File already exists.");
                    }
                }
                if (out.lastIndexOf(File.separatorChar) == -1) {
                    success = file.createNewFile();
                } else {
                    String outPath = out.substring(0, out.lastIndexOf(File.separatorChar));
                    File dir = new File(outPath);
                    if (dir.exists()) {
                        success = file.createNewFile();
                    } else {
                        dir.mkdirs();
                        success = file.createNewFile();
                    }
                }
                if (success) {
                    if (m_useRelativePath) {
                        try {
                            m_outputFile = Utils.convertToRelativePath(file);
                        } catch (Exception e) {
                            m_outputFile = file;
                        }
                    } else {
                        m_outputFile = file;
                    }
                    setDestination(new FileOutputStream(m_outputFile));
                }
            } catch (Exception ex) {
                throw new IOException("Cannot create a new output file (Reason: " + ex.toString() + "). Standard out is used.");
            } finally {
                if (!success) {
                    System.err.println("Cannot create a new output file. Standard out is used.");
                    m_outputFile = null; // use standard out
                }
            }
        }
    }

    /**
     * Sets the destination output stream.
     * 
     * @param output the output stream.
     * @throws IOException throws an IOException if destination cannot be set
     */
    @Override
    public void setDestination(OutputStream output) throws IOException {

        m_writer = new BufferedWriter(new OutputStreamWriter(output));
    }

    /**
     * Sets the directory and the file prefix. This method is used in the
     * KnowledgeFlow GUI
     * 
     * @param relationName the name of the relation to save
     * @param add          additional string which should be part of the filename
     */
    @Override
    public void setDirAndPrefix(String relationName, String add) {

        try {
            if (m_dir.equals("")) {
                setDir(System.getProperty("user.dir"));
            }
            if (m_prefix.equals("")) {
                if (relationName.length() == 0) {
                    throw new IOException("[Saver] Empty filename!!");
                }
                String concat = (m_dir + File.separator + relationName + add + FILE_EXTENSION);
                if (!concat.toLowerCase().endsWith(FILE_EXTENSION) && !concat.toLowerCase().endsWith(FILE_EXTENSION + FILE_EXTENSION_COMPRESSED)) {
                    concat += FILE_EXTENSION;
                }
                setFile(new File(concat));
            } else {
                if (relationName.length() > 0) {
                    relationName = "_" + relationName;
                }
                String concat = (m_dir + File.separator + m_prefix + relationName + add);
                if (!concat.toLowerCase().endsWith(FILE_EXTENSION) && !concat.toLowerCase().endsWith(FILE_EXTENSION + FILE_EXTENSION_COMPRESSED)) {
                    concat += FILE_EXTENSION;
                }
                setFile(new File(concat));
            }
        } catch (Exception ex) {
            System.err.println("File prefix and/or directory could not have been set.");
            ex.printStackTrace();
        }
    }

    /**
     * to be pverridden
     * 
     * @return the file type description.
     */
    @Override
    public abstract String getFileDescription();

    /**
     * Tip text suitable for displaying int the GUI
     * 
     * @return a description of this property as a String
     */
    public String useRelativePathTipText() {
        return "Use relative rather than absolute paths";
    }

    /**
     * Set whether to use relative rather than absolute paths
     * 
     * @param rp true if relative paths are to be used
     */
    @Override
    public void setUseRelativePath(boolean rp) {
        m_useRelativePath = rp;
    }

    /**
     * Gets whether relative paths are to be used
     * 
     * @return true if relative paths are to be used
     */
    @Override
    public boolean getUseRelativePath() {
        return m_useRelativePath;
    }

    /**
     * generates a string suitable for output on the command line displaying all
     * available options.
     * 
     * @param saver the saver to create the option string for
     * @return the option string
     */
    protected static String makeOptionStr(AbstractFileSaver saver) {
        StringBuffer result;
        Option option;

        result = new StringBuffer();

        // build option string
        result.append("\n");
        result.append(saver.getClass().getName().replaceAll(".*\\.", ""));
        result.append(" options:\n\n");
        Enumeration<Option> enm = saver.listOptions();
        while (enm.hasMoreElements()) {
            option = enm.nextElement();
            result.append(option.synopsis() + "\n");
            result.append(option.description() + "\n");
        }

        return result.toString();
    }

    /**
     * runs the given saver with the specified options
     * 
     * @param saver   the saver to run
     * @param options the commandline options
     */
    public static void runFileSaver(AbstractFileSaver saver, String[] options) {
        // help request?
        try {
            String[] tmpOptions = options.clone();
            if (Utils.getFlag('h', tmpOptions)) {
                System.err.println("\nHelp requested\n" + makeOptionStr(saver));
                return;
            }
        } catch (Exception e) {
            // ignore it
        }

        try {
            // set options
            try {
                saver.setOptions(options);
            } catch (Exception ex) {
                System.err.println(makeOptionStr(saver));
                System.exit(1);
            }

            saver.writeBatch();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}
